#include <stdio.h>
int sum(int,int);
int product(int,int);
int difference(int,int);
int main(void){
  int a = 10;
  int b = 5;
  int result = 0;
  int (*pfun[10])(int,int);
  
  pfun[0]=sum;
  pfun[1]=product;
  pfun[2]=difference;
  for(int i=0;i<3;++i){
    result=pfun[i](a,b);
    printf("result = %2d\n",result);
  }
  
  result=pfun[1](pfun[0](a,b),pfun[2](a,b));
  printf("The product of the sum and the difference = %2d\n",result);
  
return 0;
}

int sum(int x,int y){
  return x+y;
}

int product(int x,int y){
  return x*y;
}

int difference(int x,int y){
  return x-y;
}
